1. Field of the Invention
This invention relates to an apparatus and a methodology to determine the presence and/or concentration of certain metabolites or other substances occurring within a certain medium, such as and without limitation, blood, urine, and saliva. In one embodiment the apparatus and methodology utilizing the principles of the invention is adapted for use as a birth management tool.
2. Background of the Invention
Many types of "home-based" testing apparatuses exist to determine the presence and/or concentration of substances such as metabolites occurring within some medium. While these prior "home-based" testing apparatuses often adequately determine the presence of some of these substances, such as metabolites, they are not capable of determining the concentration or, in many cases, even the presence of such target substances when the concentration of these metabolites or other substances is less than about 10.sup.-6 M. In these cases, relatively complex and costly laboratory tests must be done, usually by one or more trained technicians, in order to ascertain the presence and/or concentration of these substances. There is therefore a great need for a technique (hereinafter the term "technique" as used in this Application refers to both an apparatus and a methodology) to reduce health care cost by providing a relatively inexpensive and relatively easy to use "home-based" testing apparatus to determine the presence and/or concentration of certain substances or metabolites. Applicant's invention addresses and fulfills this need. Moreover, there is also a great need for a "real time" diagnostic technique that will provide reliable data concerning the presence and/or concentration of certain metabolites and other substances occurring within a certain medium and which will allow an individual to take a prompt action in response to the diagnostic indications. Applicant's invention provides such a "real time" diagnostic indication.
Particularly, Applicant has found that these various needs are particularly acute in the field of birth control and birth management and that Applicant's invention, in one embodiment, is particularly suited for use in birth control and birth management. That is, it has been deduced form a retrospective study of family planning records that about 90% of all conceptions occur within about a five day period which probably spans the day of the peak concentration of the luteinizing hormone occurring and/or most often sensed within human urine, and more particularly, probably spans from about two days before this peak occurs until about three days after the peak arrives. It is known that during this fertile period, sexual intercourse may lead to pregnancy. Hence, many of the current "home-based" birth management techniques utilize some sort of color changeable paper to notify the users of the pending fertility period by measuring the concentration of the luteinizing hormone. While somewhat useful, these prior techniques provide notification of the impending ovulation no more than thirty-six hours prior to the onset of the fertile period. Since the average longevity of sperm in the vagina is about forty-eight hours, these prior "home-based" tests do not detect the start of the fertility cycle sufficiently early to reliably prevent conception and/or to actually "manage" the conception process.
It is known that the 17-estradiol metabolite, estrone-3-glucuronide (commonly referred to by those of ordinary skill in the art as "E1-g") reaches about 85% to about 95% of its peak value in human urine within about 72 hours prior to the onset of ovulation. Hence, the concentration measurements of E1-g in urine, as Applicant has found, provides a reliable advance warning of the onset of ovulation, sufficient to prevent conception since the time of warning is longer that the lifetime of sperm in the vagina and sufficient to allow individuals to "manage" conception (e.g. actively determine and plan when conception should begin). Prior "home-based" techniques are not readily able to measure E1-g within the urine because the gradual monotonic peak of E1-g requires a more quantitative detection device than current tests provide. Moreover, the World Health Organization has determined the "home-based" E1-g birth management systems would be of great utility in managing the world's population and would be especially useful in overpopulated and developing countries since birth management could be achieved (e.g. birth control could be achieved by abstinence during the ovulation period while conception could be more readily achieved by sexual intercourse during ovulation). Applicant's invention, in one embodiment, provides such an E1-g sensing and/or testing apparatus for use in "home-based" birth management and provides the utility sought in the developing and overpopulated countries. Applicant's invention is therefore an advance in the art of birth management and contains general inventive principles which have a wide use in many other areas of sensing systems.